Effect of graded nerve pressure injuries on motor function

OBJECT

The purpose of this study was to determine the minimum amount of nerve fibers required to maintain normal motor function after nerve injury in rats.

METHODS

The authors first confirmed that a common peroneal nerve injury caused more aggravating effects on lower limb motor function than tibial nerve injury, as assessed by the static sciatic index (SSI). Thereafter, rats were subjected to varying degrees of crush injury to the common peroneal nerve. At 48 hours after the injury, motor function was assessed using the SSI and slope-walking ability (with slope angles of 30° and 45°). The tibialis anterior muscle, a main muscle innervated by the common peroneal nerve, was removed. Muscle sections were co-labeled with neuronal class III β-tubulin polyclonal antibody to identify the presence of axons and Alexa Fluor 488-conjugated α-bungarotoxin to identify the presence of motor endplates.

RESULTS

The evaluation of neuromuscular innervation showed a correlation between SSI scores and ratios of residual axons (rs = 0.68, p < 0.01), and there was a statistically significant difference between slope-walking ability and ratios of residual axons (p < 0.01). Moreover, the ratios of residual axons in the nerve-crushed rats with normal motor function (SSI above -20) ranged from 36.5% to 88.7%, and those ratios in the success group with slope-walking angles of 30° and 45° ranged from 14.7% to 88.7% and from 39.8% to 88.7%, respectively.

CONCLUSIONS

In this study of rodents, less than half of the motor axons were sufficient to maintain normal motor function of the lower limb.

Two specific tongue regions receive bilateral hypoglossal innervation: a study in neonatal rat pups

OBJECTIVE

The purpose of this study was to investigate the functional role of bilateral hypoglossal (XII) nerve innervation of the tongue.

MATERIALS AND METHODS

The possibility of bilateral innervation of XII nerve in the tongue was examined using postmortem fibre tracing in normal neonatal rats. In addition, immunohistochemical testing for synaptophysin or vesicular acetylcholine transporter (VAChT) was carried out in unilaterally XII nerve-resected neonatal rats.

RESULTS

Postmortem fibre tracing revealed constant distribution of the nerve fibres extending across the midline and existence of bilateral innervated area in the rostroventral and caudodorsal regions of the tongue. Synaptophysin-positive and VAChT-positive nerve terminals were also distributed continuously from the XII nerve-intact to the nerve-resected side across the midline of the tongue. The contralaterally projecting VAChT-positive nerve terminals were more numerous in suckling P2 rats (6.6 ± 0.5/section) than those in non-suckling P2 rats (4.9 ± 0.3/section) 24 h after nerve resection. Furthermore, the contralaterally projecting VAChT-positive nerve terminals were more numerous in P7 rats with nerve resection on P1 (6.3 ± 0.2/section) than those in P7 rats with nerve resection on P6 (3.1 ± 0.8/section).

CONCLUSION

We concluded that neonatal rats have two specific tongue regions receiving bilateral XII innervation, which allowed suckling in unilaterally XII nerve-resected neonatal rats.

Stereological estimation of olfactory receptor neurons in rats

The total number of olfactory receptor neurons (ORNs) in the rat main olfactory epithelium (MOE) was estimated using stereological sampling. Skulls and noses of newborn (postnatal day 0), young adult (8 weeks), and adult (6 months) rats were decalcified, embedded in paraffin, cut into 10-μm thick sections serially at 100-μm intervals, and processed for immunohistochemistry for olfactory marker protein (OMP), a specific marker of mature ORNs with fiber connections to the olfactory bulb. The number of OMP (+) receptor neurons was measured using an optical fractionator with stereological software (Stereoinvestigator). The total number of OMP (+) receptor neurons in the unilateral MOE was 0.47 × 10(6) in newborns and 21 × 10(6) in young adults and adults. Our previous study showed that the corresponding unilateral total number of neurons was 5.2 × 10(6) in young adult mice. Accordingly, we concluded that rats had 4 times more OMP (+) receptor neurons than mice at the adult stage and that the number of these neurons increased approximately 45 times between birth and maturity.

Bony Landmarks of the Anterior Cruciate Ligament Tibial Footprint: A Detailed Analysis Comparing 3-Dimensional Computed Tomography Images to Visual and Histological Evaluations

BACKGROUND

Although the importance of tibial tunnel position for achieving stability after anterior cruciate ligament (ACL) reconstruction was recently recognized, there are fewer detailed reports of the anatomy of the tibial topographic footprint compared with the femoral side.

HYPOTHESIS

The ACL tibial footprint has a relationship to bony prominences and surrounding bony landmarks.

STUDY DESIGN

Descriptive laboratory study.

METHODS

This study consisted of 2 anatomic procedures for the identification of bony prominences that correspond to the ACL tibial footprint and 3 surrounding landmarks: the anterior ridge, lateral groove, and intertubercular fossa. In the first procedure, after computed tomography (CT) was performed on 12 paired, embalmed cadaveric knees, 12 knees were visually observed, while their contralateral knees were histologically observed. Comparisons were made between macroscopic and microscopic findings and 3-dimensional (3D) CT images of these bony landmarks. In the second procedure, the shape of the bony prominence and incidence of their bony landmarks were evaluated from the preoperative CT data of 60 knee joints.

RESULTS

In the first procedure, we were able to confirm a bony prominence and all 3 surrounding landmarks by CT in all cases. Visual evaluation confirmed a small bony eminence at the anterior boundary of the ACL. The lateral groove was not confirmed macroscopically. The ACL was not attached to the lateral intercondylar tubercle, ACL tibial ridge, and intertubercular space at the posterior boundary. Histological evaluation confirmed that the anterior ridge and lateral groove were positioned at the anterior and lateral boundaries, respectively. There was no ligament tissue on the intercondylar space corresponding to the intercondylar fossa. In the second investigation, the bony prominence showed 2 morphological patterns: an oval type (58.3%) and a triangular type (41.6%). The 3 bony landmarks, including the anterior ridge, lateral groove, and intertubercular fossa, existed in 96.6%, 100.0%, and 96.6% of the cases, respectively.

CONCLUSION

There is a bony prominence corresponding to the ACL footprint and bony landmarks on the anterior, posterior, and lateral boundaries.

CLINICAL RELEVANCE

The study results may help create an accurate and reproducible tunnel, which is essential for successful ACL reconstruction surgery.

Japanese strategies to maximize heart and lung availabilities: experience from 100 consecutive brain-dead donors

OBJECTIVE

Because the donor shortage is extremely severe in Japan because of a strict organ transplantation law, special strategies have been established to maximize heart and lung transplantations (HTs and LTs, respectively). We reviewed 100 consecutive brain-dead donors to evaluate our strategies to identify and manage heart and lung donors.

METHODS

We retrospectively reviewed all 100 consecutive brain-dead donors procured since the law was issued in 1997. There were 56 mens and the overall mean donor age was 43.5 years. The causes of death were cerebrovascular disease (n = 62), head trauma (n = 20), and asphyxia (n = 16): Since November 2002, special transplant management doctors were sent to donor hospitals to assess cardiac and lung functions, seeking to identify transplant opportunities. They stabilized donor hemodynamics and lung function by administering antidiuretic hormone intravenously and performing bronchofibroscopy for pulmonary toilet.

RESULTS

Seventy-nine HTs, 1 heart-lung transplantations, and 78 LTs (46 single and 32 bilateral) were performed. By applying these strategies organs per donor were increased from 4.5 to 6.8. Among heart donors, 61/80 were marginal: high inotrope requirement (n = 29), cardiopulmonary resuscitation (n = 28), and/or >55 years old (n = 20). None of the 80 HT recipients died of primary graft failure (PGF). Patient survival rate at 10 years after HT was 95.4%. Among lung donors, 48/65 were marginal: pneumonia (n = 41), chest trauma (n = 4), and >55 years old (n = 9). Only 2/78 LT recipients died of PGF. Patient survival rate at 3 years after LT was 72.2%. After inducing frequent pulmonary toilet, lung procurement and patient survival rates increased significantly after LT.

CONCLUSIONS

Although the number of cases was still small, the availability of organs has been greater and the outcomes of HT/LT acceptable.

Stereological quantification of olfactory receptor neurons in mice

The total number of olfactory receptor neurons (ORNs) in the mouse main olfactory epithelium (MOE) was estimated using stereological sampling. Noses and skulls of male and female 8-week-old C57BL/6J mice were de-calcified, embedded in paraffin, cut into 10-μm-thick sections serially at 100-μm intervals, and processed for immunohistochemistry for the olfactory marker protein (OMP), a specific marker for ORNs. The number of OMP (+) receptor neurons was measured using an optical fractionator with the Stereo-Investigator software. The mean values of the total number of OMP (+) receptor neurons in the unilateral MOE were 5,140,000±380,000 in males and 5,210,000±380,000 in females, with no significant differences between the sexes. We concluded that the total number of ORNs in the unilateral MOE is approximately 5×10(6) in mice.

Correlation between motor function and axonal morphology in neonatally sciatic nerve-injured rats

The present study was conducted to investigate the correlation between motor function and axonal morphology in neonatally sciatic nerve-injured rats. The left sciatic nerve of newborn rats was transected or crushed, and functionality of the sciatic nerve was assessed by the static sciatic index after 8 weeks. After functional assessment, the common peroneal nerves in the control, nerve-transected, and nerve-crushed rats were removed and prepared for morphometric examinations. The cross-sectional area of the nerve, total number of myelinated axons, and size of each myelinated axon were analyzed for each group. The control rats showed normal motor function, whereas the nerve-transected rats showed severe motor dysfunction. The cross-sectional area of the nerve and total number of myelinated axons were reduced after nerve transection. Moreover, the percentage per size class of myelinated axons was almost uniform in the control rats, while the distribution was shifted to the left in the nerve-transected rats. Furthermore, no large myelinated axons were observed in the nerve-transected rats. The nerve-crushed rats showed various gait functions with various distribution patterns of axonal size, and the rats were divided into two groups with and without uninjured residual large axons. The results showed that the importance of regenerated medium-sized axons in cases without large axons and of residual large axons in cases with large axons in motor function. It was revealed that motor function was related closely to axonal size in neonatally nerve-injured rats.

Quantitative analysis of survival of hypoglossal neurons in neonatally nerve-injured rats: Correlation with milk intake

INTRODUCTION

Tongue movement innervated by the hypoglossal (XII) nerve is essential for the survival of neonatal rats. The pups with bilateral XII nerve resection failed to suckle milk and did not survive, and the pups with unilateral XII nerve resection showed disturbed suckling capability and lower survival rates. The present study was performed to investigate the relation between neuronal population and milk intake of developing rats that had received various degrees of crush injuries to the unilateral XII nerve during the neonatal period.

METHODS

The right XII nerve of postnatal day 1 (P1) pups was crushed and milk intake was estimated at 3 days and 6 days after the nerve injury. As nerve injury at the neonatal stage results in death of axotomized neurons, varying degrees of crushing was estimated by the number of survived motor neurons.

RESULTS

In nerve-crushed rats, the populations of XII motor neurons and amounts of milk intake were reduced in a varied manner. Statistically significant positive correlations were observed between increasing XII neuron survival and increasing milk intake at 3 (r=0.62) and 6 (r=0.71) days after the nerve injury.

CONCLUSION

The results indicate that there is a strong relationship between the number of XII motor neurons and the amount of milk intake in neonatally XII nerve-injured rats.

Neoadjuvant chemotherapy with S-1 and cisplatin followed by D2 gastrectomy with para-aortic lymph node dissection for gastric cancer with extensive lymph node metastasis

BACKGROUND

Locally advanced gastric cancer with extensive regional and/or para-aortic lymph node (PAN) metastases is typically unresectable and associated with poor outcomes. This study investigated the safety and efficacy of S-1 plus cisplatin followed by extended surgery with PAN dissection for gastric cancer with extensive lymph node metastasis.

METHODS

Patients with gastric cancer with bulky lymph node metastasis along the coeliac artery and its branches and/or PAN metastasis received two or three 28-day cycles of S-1 plus cisplatin, followed by gastrectomy with D2 plus PAN dissection. The primary endpoint was the percentage of complete resections with clear margins in the primary tumour (R0 resection). A target sample size of 50 with one-sided α of 0.105 and β of approximately 0.2 corresponded to an expected R0 rate of 65 per cent and a threshold of 50 per cent.

RESULTS

Between February 2005 and June 2007, 53 patients were enrolled, of whom 51 were eligible. The R0 resection rate was 82 per cent. Clinical and pathological response rates were 65 and 51 per cent respectively. The 3- and 5-year overall survival rates were 59 and 53 per cent respectively. During chemotherapy, grade 3/4 neutropenia occurred in 19 per cent and grade 3/4 non-haematological adverse events in 15.4 per cent. The incidence of grade 3/4 adverse events related to surgery was 12 per cent. There were no reoperations or treatment-related deaths.

CONCLUSION

For locally advanced gastric cancer with extensive lymph node metastasis, 4-weekly S-1 plus cisplatin followed by surgery including PAN dissection was safe and effective for some patients. Further investigation of this treatment strategy is warranted.

Donor evaluation and management system (medical consultant system) in Japan: experience from 200 consecutive brain-dead organ donation

PURPOSE

As the donor shortage is extremely severe in Japan because of a strict Organ Transplantation Act, special strategies must be established to maximize organ transplant opportunities. The purpose of this study was to evaluate our strategies to identify and manage 200 consecutive brain-dead organ donors.

METHODS AND MATERIALS

We retrospectively reviewed the 200 donors procured since the Organ Transplantation Act was issued in 1997, including 118 males, a mean overall age of 45.1 years and cause of death being cerebrovascular disease (n = 119), head trauma (n = 37), and asphyxia (n = 44). DONOR EVALUATION AND MANAGEMENT SYSTEM: Since November in 2002, special transplant management doctors ("medical consultants") were sent to donor hospitals to assess organ function and identify transplantable organs. They also provided intensive care to stabilize hemodynamics and improve cardiac and lung functions by administering antidiuretic hormone intravenously and providing bronchofiberscopic pulmonary toilet.

RESULTS

We obtained 146 heart, 1 heart-lung, and 154 lung (87 single and 67 bilateral), 175 liver (28 splitted liver), 142 pancreas (114 pancreas-kidney), 253 kidney and 12 small bowel grafts. Organs procured from 1 donor increased from 4.5 to 6.8 after applying these strategies.

CONCLUSIONS

Although the number of cases was still small, the availability of organs and outcomes of transplantation have been acceptable.

Current status of in-hospital donation coordinators in Japan: nationwide survey

OBJECTIVES

When the Japanese Organ Transplantation Act was issued, the Japanese Organ Transplantation Network (JOT) was established in 1997. JOT lists recipients, assesses and manages organ donors, and educates publics and headquarters for organ donations. JOT procurement transplant coordinators (PTC) play roles in obtaining consent from relatives for organ donation, donor evaluation and management, organ recovery management, organ transport, and care of donor families during and after donation. Every prefecture has at least one PTC who is mainly working in public education and hospital development. They also help the JOT PTC at the time of organ procurement. Most prefectures commission hospital staff in the procurement hospital to be an in-hospital PTC (In-Hp PTC), who make their hospital staff aware of organ donation and support organ procurement. Although the Act was revised in 2010 with brain-dead organ donation increased from 13 to 44 cases yearly, the number was still extremely smaller than other developed countries. In these circumstances, In-Hp PTC may play greater roles to increase donation and smooth procurement procedures Our primary aim was to describe the current status of In-Hp PTC in Japan.

MATERIALS AND METHODS

Between December 15, 2011, and January 31, 2012, we invited 1889 In-Hp PTC to complete a letter survey using a self-designed questionnaire. In all, 56 In-Hp PTC (40%) completed and returned it.

RESULTS

The occupation of the respondents was nurse (66%), physician (18%), or other (16%). Although 52% of respondents belonged to the hospital, which was designated for brain-death organ donation by the government, only 46% had any experience with a cadaveric donor. Only 2% were full-time In-Hp PTC. They mainly played a role in preparing their own manual for organ procurement (57%), providing in-hospital lectures (44%) or their own simulation exercise (29%), as well as coordinating donation cases. Although 77% had attended seminar about organ donation provided by JOT or the prefecture PTC, 93% wanted more professional education. However, it was difficult for them to attend these activities, to manage a rare and sudden donation case, and to find time to learn about organ donation because they had another post. The topics that they wanted to learn were donor family care (72%), overall organ/tissue donation procedures (65%), the role of In-Hp PTC (67%), simulations of donation (65%), legislation and social system of organ donation (61%), medical indications for donation (61%), current status of donation and transplantation in Japan (57%), donor management (56%), and case studies (49%). There were significant variations in the topics of interest among the occupations. As they had another post, they could find only a short period (1 or 2 days) to take professional education, such as lectures. Therefore, it was difficult for them to attend practical on-the-job training.

CONCLUSIONS

To establish an organ procurement system and increase organ donation, In-Hp PTC have important roles in Japan. However, none is a full-time In-Hp PTC. Most In-Hp PTC require more professional education. A systematic education program for each occupation must be established soon.

Analysis of spontaneous regeneration of olfactory structures with emphasis on myelination and re-innervation of cortical areas

Regeneration of the lateral olfactory tract (LOT) occurs spontaneously after transection in developing rats. In neonatally LOT-transected rats, we observed a newly formed myelinated tract near the rhinal sulcus. The aim of this study was to analyze the precise re-innervated cortical areas and to demonstrate ectopic LOT myelination in neonatally LOT-transected rats. Neonatal rats were subjected to unilateral LOT transection and simultaneous injection of a retrograde fluorescent tracer into the posterior olfactory cortex to evaluate the degree of transection. After 8 weeks, bilateral olfactory bulbs of the rats were subjected to multiple injections of an anterograde neuronal tracer to determine the extent of the regenerated fibers. In the completely LOT-transected rats, the regenerated fibers were distributed in the anterior olfactory cortices; the anterior olfactory nucleus, the olfactory tubercle, and the rostral part of the piriform cortex. Ectopic myelination of LOT was evident immediately below the rhinal sulcus in the completely and incompletely LOT-transected rats. We concluded that the regenerated bulbar fibers were confined to the regions of the anterior olfactory cortices and that ectopic myelination of the regenerated LOT occurred only at a specific site near the rhinal sulcus.